A Matter of Logic
by sarit halivana
Summary: PreHBP. Dark Wizards discover the power of logic, along with the key to circumventing the wards protecting Harry. When a perfectly normal scene in front of 4 Privet Drive strikes a member of the Order as an unusual sight, alarm rings squirm and an invest
1. Expectations

**Disclaimer**: Playing with borrowed toys

A Matter of Logic

Chapter One: Expectations

Sweat gleamed on the forehead of a darkly clad man. The man brought a pale, sure hand to his brow to wipe away glistening beads, brushing black, greasy locks from his face in the process. The temperature beneath the invisibility cloak was dizzying. Heat radiated from the sun cooked asphalt of Privet Drive.

Severus Snape scowled at the dying lawn of the Dursley residence. It was his turn on the rotation to protect Potter, and he was less than pleased.

This was his fifth rotation, and he had seen the Potter boy twice. Both times the whelp seemed to be wearing a walking whale's clothing. Both times the brat had been working efficiently toward one end or other, gardening or otherwise maintaining the aesthetic aspects of his home. Both times his aunt had come out to chastise him for some misdeed or other, though even Snape, ready as he was to find fault with the boy, could not fathom what the child might have done. Perhaps the woman was simply temperamental.

"Come along, Harry dear," said Petunia Dursley as she opened the white screen door of the house, and set one bony, sandaled foot onto the red stoop. "Your uncle will be home any moment, and you know how excited he'll be to see the work you've done on the garden. It might even be early enough for the two of you to do some gardening together." Petunia Dursley smiled lovingly as the Potter boy strutted onto the yard. "He'll be pleased when I show him what I've done with the flowerbed," said the insolent brat. "I know he'll think it brilliant." Arrogant. Arrogant, Potter, like his arrogant father…

Except, that wasn't right. Severus had come to expect a different vein of arrogance from Potter – an arrogance that got people killed, an arrogance in his actions more than in his words. Potter was arrogant, but this was different. Potter now held himself more like James had, and the words – his language consisted of terms and a tone that Severus would have expected the boy's father to have used.

Intrigued, Snape turned his attention back to the scene before him. Potter's aunt was dragging a lawn chair across the grass, bringing it to a spot where she had placed a novel and a glass of lemonade. As Petunia unfolded the chair, Potter propped himself up against the trunk of a large tree and pulled out a snitch. He let it go, paused a moment, then caught the fluttering orb before it could vanish.

The scene was unnaturally reminiscent of Potter Senior at Hogwarts. The untidy black hair, the light brown eyes… no, green eyes. The green eyes were as bright as ever, the scar on the boy's forehead as stark as he remembered. But Snape knew what he had seen. Something was off here. Snape touched a glass lemon drop in his pocket, refraining from sneering at the thought of the man who had insisted on this ridiculous trinket as a form of communication. The lemon drop heated slightly in Snape's pocket, causing a silver ring on Dumbledore's left hand to squirm.

Snape remained perfectly still as he stood outside Potter's residence, waiting for the Headmaster to arrive. The woman and boy persisted in their chosen means of relaxation, and all seemed calm. Clearly, the idiotic child had landed himself in some trouble. What foolishness the boy had engaged in, in order to bring this about, was something he did not want to contemplate until he had some solid facts on which to base his theories.

Within fifteen minutes of Snape signaling the Headmaster, a lemon drop hit the sidewalk a foot from where he stood. The Headmaster was here, and invisible.

Snape presently began to relay the situation in a low hiss, looking downward as he spoke, so as not to have to look through the Headmaster, or three inches to his left. "Potter's behavior since he and his aunt first exited the house has been strange," whispered Snape, sparing not a moment for pleasantries. "At first, his mien was so reminiscent of his father's," Snape favored Dumbledore with a wry sneer, "it seemed to warrant closer inspection. When I looked at his eyes, I first saw brown, causing me to suspect something a bit more sinister than I had initially credited. That's when I alerted you."

The Headmaster surveyed the scene. "I see what you described, Severus, but I do not believe my eyes: I think they are being deceived. Nor am I convinced that what I see is what I first saw." _Typical Dumbledore statement that will make sense once the utility of the information has expired, _thought Severus. The Headmastere sighed. Dumbledore's eyes did not twinkle, and the sad weight in his voice dulled Snape's ire. "It is a mark of my great failure that I know something to be amiss because I see Harry being treated well by his relatives."

"That is not something you would expect to see," Snape deduced, his voice flat despite his curiosity.

"Expectations are a powerful tool, Severus, and I believe it is you who saw what you expected to see," replied Dumbledore. Snape considered the man. The idea held merit: he saw what he believed he would have seen on his first shift, nay, at Potter's first appearance at Hogwarts. He saw James Potter playing with a snitch, and that worried him.

"If I see what I expect to see, and in voicing it have caused you to see this same vision of Potter," Snape correctly interpreted the Headmaster's implications, "what is actually going on behind this façade?"

"An excellent question, Severus," said Dumbledore, as he withdrew his wand from his robe pocket and directed it at the sight in front of him. "Liberus," whispered Dumbledore six times in quick succession, forming six parabolas in the air as he did so. Petunia and Harry remained immersed in their activities, oblivious to the wizards standing in front of their gate.


	2. Potions

Disclaimer: Traipsing about in someone else's imagination – I am not earning a profit on anything I post here.

Chapter Two: Potions

Dumbledore lowered his wand in defeat; the Order members around him followed suit. Eight hours had elapsed since the Headmaster had first set foot on Privet Drive, four since all but Snape had abandoned any pretense of concealment. Dumbledore's spy had just returned to him, informing him that he could not contact Malfoy, McNair, LeStrange, Nott or Goyle. He had reached Crabbe, but the man did not seem to have any information, and he did not dare press for it beyond vague inquiries. Severus was certain Crabbe would not become suspicious of the questions he had asked, but he had no desire to wear his luck thin. Number Four Privet Drive was under attack, and the Order could divine neither the nature of the attack nor the location of the attackers. The scene in the yard remained pleasant, and all saw that for the sign of ill fortune that it was. Spell after spell had failed to reveal what was occurring behind a veil so filled with shadow and deceit that one of the greatest wizards of the century could not penetrate the shallow illusion.

"Enough," said Dumbledore, much to the surprise of the Aurors, sneaks, thieves, heroes, spies that filled his ranks. "The worst I feared seems to be the reality of the situation. Let us unite quickly to discuss how we might combine our strengths to defeat the deception we our faced with. Here is not he place." The men and women gathered around Harry Potter's summer domicile exchanged a few wary, concerned, confused and exhausted glances before Apparating to the outskirts of Headquarters. Thirteen Order members crowded the dining room of 12 Grimmauld Place. Snape sneered at the memory of Trelawney's reaction to the same number at dinner three Christmases ago as he counted those present, and wondered what scheme the Headmaster might have in mind for dissolving the impenetrable impression of peacefulness that distressed the Order so.

"We need a new plan of action. Time might be running short, and we know virtually nothing of what is going on behind what I will call a Glamour for now," said Dumbledore, for the Order had deduced that what they were facing was indeed a version of the spell they were accustomed to encountering.

"Mundungus, please procure as much powdered dementor skin and eye of hinkypunk as you can manage," said Dumbledore to the ill-kempt, foul-smelling man who had joined them not a quarter of an hour earlier. Where he had been and what he had been doing the past eight hours Severus didn't care to fathom, but he appreciated the relative clearness of the air once the shutting of the heavy oak doors marked the rank man's exit.

"Severus," sharp black eyes locked Dumbledore's hard blue, "please take the necessary steps to begin the brewing of the Hastaklah potion." A slight hitch in Snape's breathing was the only physical evidence of the shock Snape experienced upon receiving this order. The fact that any tangible evidence of the emotion that registered within him had become manifest was testament enough to the shock that coursed through him. That was a potion the Dark Lord might have asked him to brew. Composed once more within a fraction of a moment, Severus stalked to the Floo and returned to his dungeon lab.

Severus had argued with the Headmaster once about whether a table existed. Dumbledore maintained that it was possible that it did not; Severus set his glass of absinthe on the table and argued that since the glass did not fall through, it existed for his purposes. The Headmaster told Snape that his expectations might be a fundamental and causative element of the observed results; he called him a pragmatist and Severus embraced the title unabashedly. Dumbledore then made the table disappear. Severus was annoyed: he had intended on finishing that drink. The Headmaster at least had the grace to replenish the cup.

_He is my master, I his servant, and that is why_, thought Severus scathingly as he recalled the memory. The Headmaster had filled his glass, whereas his previous avenue of loyalty would have led him to nothing but torture and pain. Should his logic have been found lacking by the Master he had sworn himself to in word and deed while still a student at Hogwarts, his lesson would not have been without lasting consequence. Now Snape had once again the opportunity to contemplate the role of expectations. He saw what he believed he ought to see, much as though he were looking through the eyes of Deceit itself.

Three clockwise stirs, nine counterclockwise, five clockwise, lower the flame.

Three, nine, five – the soul.

Six clockwise stirs.

Six, zero, zero – a lie.

Seven is perfection.

Six imperfection.

Three is infinite.

Infinity and zero – Muggle churches banned these concepts when they saw their power.

Zero – the limit of our achievement as our aspirations near infinity.

Six, six, and six – infinite imperfection.

Stir. Stir. Stir.

The soul. The lie.

_What will we see in a soul that is fraudulent?_

Add powdered dementor skin, remove the soul.

_Did the Dark Lord turn the illusion into a Horcrux? I thought Horcruxes had to be contained in physical objects, perhaps not…_

Now we have only the lie, the deception.

Add eye of hinkypunk: eyes are the window to the soul, hinkypunks cause misdirection – avoid the deception, steer clear of the falsity where his soul, your soul seeks to guide you.

_Here is your potion. What now Albus? _


	3. Chapter 3

Disclaimer: Traipsing about in someone else's imagination – I am not earning a profit on anything I post here.

Chapter 3: Logic

Severus Snape sat in a straight backed chair at Number 12 Grimmauld Place. He observed those seated around the same dark table – Dumbledore, Minerva, Tonks, Lupin and Shacklebolt. Three days had passed since Operation Sight had begun, and they had made little headway. Little was preferable to none, though, and they held hope that their minor discoveries would coalesce into a greater revelation of what they faced.

"Remus, what have you to report?" enquired Dumbledore as the others settled around the table.

"Werewolves, as far as I can gather, have no involvement in this attack. However, one of my contacts who has been working to unite dark creatures in order to increase their bargaining power with the ministry made an offhanded comment about his inability to make contact with the dementors since Tuesday. The timing is suspect."

"That is cause for concern," said the aged Headmaster, "Severus, what of your potion?"

"The potion will be ready by nightfall. If my interpretation of your plans and the inferences that you have made are correct, I believe the potion will be effective. The question remains, how will you apply a potion to a spell? Or did the nature of the alteration allow some sort of physical anchor to be used for the spell, which we can hope to breach?"

Remus, and Tonks exchanged looks, wondering whether Snape had begun channeling Dumbledore or they had devised a new system of communication that made sense to none but themselves.

"Might I enquire as to what spell this potion will be applied to? Is it actually an altered glamour, and if so, have we made any headway into determining the nature of the alteration?" asked Minerva, irked at the thought that Snape had been trusted with more information than herself.

"All in good time, Minerva, all in good time. My knowledge remains very much in the hypothetical stage." Dumbledore smiled at his deputy, allaying her irritation. "Have you anything else to report, Severus?"

"I do. I contacted Lucius, and his gloating arrogance has proved invaluable. He made an offhanded comment about the brilliance of Our Lord," Snape took a sick pleasure in horrifying the other Order members by referring to his master as such, "in finding use in the useless. I'm not certain if my interpretation is accurate, but I am confident in inferring that 'useless' equates to 'muggle,' and that the use of some muggle technology has been employed either to locate or to attack Potter. Knowing the Dark Lord, he would already have alerted the world to the fact of his success if Potter had been defeated. Lucius's tone implied that the use of the useless had already lead to success, and I therefore believe that whatever muggle method was engaged in this offensive, it enabled the Dark Lord to find Potter. It seems he has once again encountered a spot of trouble when it comes to finishing the boy off." Snape's last words were accompanied by a sneer, though he wasn't quite sure if it was directed at Potter or the Dark Lord. Potter for his endless supply of Idiot Gryffindor Luck, and the Dark Lord for his continued fruitless attempts, he decided.

"Nymphadora, how has your mission faired?" interjected Dumbledore, before any of the others could rise to Harry's defense, as Snape's tone left little doubt just how grieved he would be were Harry indeed to be 'finished off.'

Tonks perked up at Dumbledore's inquiry, as did her hair. The short, soft pink locks spiked slightly atop her head, and her cheeks flushed a shade to match her locks in her excitement.

"Excellent," said Tonks brightly. "The ministry will be completely off our backs. Apparently whatever shield You-Know-Who put up has disabled the ministry's magic sensing abilities as well, so Harry is free to protect himself without fear of expulsion."

Dumbledore nodded, pleased with the news. "Kingsley, what have you learned?"

"There is a mole in the Auror's unit," sighed Kinksley, "I believe that some information about the protections surrounding the Potter house has been leaked. My suspicions are not yet confirmed, but some sensitive information not relating to anything the unit is currently working on has been accessed recently, the Potter and Longbottom files among them. The only positive aspect of this is that whoever it is, is sloppy. It might be someone outside of the department, with high level access. This person didn't trouble him or herself to detect and disable any tracking devices connected to the files, and only disabled one of the protections on the content. This means the person could have read all of the secret but none of the top secret information in the file. Of course, some knowledge can be more dangerous to the Death Eaters than no knowledge, if they operate under the assumption that they have accessed it all. This could cause them to blunder and play to our advantage. Of course, Voldemort might also suspect that Dumbledore kept the ministry in the dark about some of his machinations, and assume that his information is incomplete, leaving us once again at a disadvantage. We know the date and time of the breach, and we are working to narrow down the list of those who fit the criteria I mentioned, but I can't press for more urgency in the investigation without raising suspicion."

"That is distressing. Do we know what information has been compromised?" inquired Dumbledore.

"They know the number of wards erected by the ministry and the respective class of each. They do not know the exact spells used, the order in which they were cast, or of any interconnections among them. Naturally, they also have no knowledge of the wards you erected. The blood magic that protects Harry is also still a factor – Voldemort won't breach that one so easily. As long as his aunt and cousin live, he should be safe within the confines of their home."

The silence around the table as realization struck those gathered was palpable in its fullness.

"As long as they live, indeed," said Dumbledore with mounting concern. They had no knowledge of what was going on within the walls or the surrounding area of Number 4 Privet Drive, and it was possible, though unlikely, that Voldemort had concentrated on eliminating the Dursleys first. The ward ensuring that Harry could not be harmed at Privet Drive did not extend to his relations, and the second layer of protection that Dumbledore had placed on the home, the fidelius charm, was meant to protect the place from being found, which clearly it had been. Dumbledore still could not quite puzzle out how the charm had been circumvented, though he had his suspicions.

"Minerva, how have your feline wanderings faired? Have you noticed anything suspicious?"

"I have. I believe the attack is coming from the back of the house. The illusion seems to extend farther there, but one hapless Death Eater must have strayed slightly. I saw black robes and nothing more, as he was not facing me, but I also saw a short beam of light emitted from a wand that ended abruptly several inches past the man. I believe that to be the exact spot where the glamour ends. It is impossible to say whether any of the wards have been breached, but the attackers seem to be congregated in the area between where the wards end around the backyard and where the illusion stops, in the alley several yards past the gate. I was unable to determine the nature of the spell, and I cannot tell whether they have succeeded in dismantling any of the wards."

At this, Severus kicked himself for the fool that he was.

"Headmaster," said Snape, "if the Death Eaters can waltz back and forth through the illusion, can't we do the same?"

"Perhaps," said Dumbledore, "we will discuss the possibility. In the meantime, our force at Harry's house remains six as we dawdle here. Let us return to the scene. Severus, please stay a moment."

"Headmaster?" Snape inquired once the others had departed.

"Severus, you spoke of a muggle method being employed to determine the location of Harry's home. Lilly's sacrifice prevents anyone wishing to cause Harry harm from entering the premises. My fidelius charm prevents others from locating Harry's home. We have seen today that our magical theories are sound, but that they can be circumvented rather than breached. Do you have any idea how muggle methods might have allowed Voldemort to locate Harry?"

"I have many, but they are all rather complex. A student once described certain aspects of muggle technology to me – a Ravenclaw, naturally – and apparently they have all kinds of devices for such things. They have pieces of metal that float around the earth and track movement, though I don't know how that works. They have other technology just as complex. But I can't shake the idea that whatever method was employed, it was as simple as reading a book.

Dumbledore pondered this for a moment, then proceeded to his next area of concern.

"Simple logic, and circumvention rather than destruction, seem to be the key to things these past few days. You are the best logician I have on staff; do you have any ideas as to how the blood magic could be circumvented?"

Snape thought for a moment, then he scowled. "The charm allows for no one who wishes to cause Harry harm to enter the premises. I do not see how that would prevent a Death Eater from attacking an unseen target."

"Then that is our answer," supplied Dumbledore. "They have used a muggle method to determine his location, and are attacking the wards of a structure that they cannot see. It seems it is time for us to consult someone knowledgeable of the muggle world regarding this possibility.

"Before we do that, however, I must address another question that you raised. You have deduced much based on the potion that I asked you to brew. Your inferences are correct, and while those bound to Voldemort can enter and leave the illusion as they please, I suspect this would not work for anyone without a connection to him."

Severus rose at once, understanding what he must do.

Hermione Granger sat in a comfortable armchair, her legs folded beside her as she held a book in one hand and petted Crookshanks with the other. She was startled from her thoughts as Headmaster Dumbledore's head appeared in her fireplace.

Jumping quickly out of her seat, Hermione sprung to the fireplace.

"Headmaster, would you like to come though? How's Harry? And your old crowd? Is everything alright?"

Dumbledore held up one hand to stem the flow of questions from bright young witch. "Time is of the essence, and I will answer your questions in due course, but right now, I need you to answer a question for me. How would one muggle find the location of a second muggle?"

Fully expecting a long diatribe regarding the intricacies of muggle technology and various techniques that could be employed to this end, Dumbledore was surprised by the straightforward answer he received.

"It's simple, really. You can just look in the local directory."

"Directory?" asked Dumbledore, confused by the reference. A directory for people? Such a compilation would be scorned in the wizarding community, where secrecy was a way of life, and estates were often unplottable or otherwise protected against location by unwelcome elements.

"Of course," said Hermione, frowning, "muggles list addresses and phone numbers in a public directory, so people can find each other." A wave of concern washed over Hermione's features as the implications and dangers of such a system occurred to her. "Oh no! The Dursleys will certainly be listed," said Hermione, catching on swiftly to the reason for Dumbledore's inquiry, "would wards extend to muggle publications?"

"To an extent. No one will be able to see the location, even if they have a general idea of where it is. Rest assured, we are doing everything we can to counteract any security breach that might have resulted."

"Have you spoken to Harry? Is he safe? Has he been removed to a more secure location? Even if they can't see the place, they can attack it, oh I hope, _I hope_, they haven't found out about muggle weapons as well."

"Harry's location, as you have gathered, has been compromised" said Dumbledore, "your information has been most valuable, and please rest assured that the Order are doing everything possible to dispel the threat. Arthur and Molly Weasley have refused to leave Privet Drive and are providing constant surveillance. I also must insist that you do not repeat this information to anyone. Thank you again for your information, Hermione, I must be going now."

As the Headmaster's head disappeared from her fireplace, Hermione began to pace, calculating the degree of danger her friend might be facing and what she could do to help. If _only_ she had access to the Hogwarts library. The library! She had get to Grimmauld Place at once. She could read the books there, and Ron would be able to help. Hermione wrote a hasty note to her parents explaining where she was going before grabbing a handful of floo powder and shouting Number 12 Grimmauld Place in a voice tight with tension, but which thankfully did not crack. Hermione didn't fancy ending up in the 12th District of Grenada.


End file.
